hydr-1

1.
variant of hydro-1. before a vowel:
hydrant.

hydr-2

1.
variant of hydro-2. before a vowel:
hydride.
British Dictionary definitions for hydr-

hydr-

combining form
1.
a variant of hydro-

hydro-

combining form
1.
indicating or denoting water, liquid, or fluid: hydrolysis, hydrodynamics
2.
indicating the presence of hydrogen in a chemical compound: hydrochloric acid
3.
indicating a hydroid: hydrozoan
Word Origin
from Greek hudōr water
hydr- in Medicine

hydr- pref.
Variant of hydro-.